Method of making concrete building blocks



-0V. 23, 1937. J STRAUB 2,099,946

METHOD OF MAKING CONCRETE BUILDING BLOCKS Filed Jan 21, 1956 2 Sheets-Sheet l IN V EN TOR.

' A T TORNEYZ NOV. 23, 1937. J STRAUB 2,099,946

METHOD OF MAKING CONCRETE BUILDING BLOCKS Filed Jan. 21, 1936 2 Sheets-Sheet 2 INVENTOR.

izwzx Patented Nov. 23, 1937 METHOD OF MAKING CONCRETE BUILDING BLOCKS Francis J. Straub, New Kensington, Pa.

Application January 21,

3 Claims.

My invention consists of an improved method or process of making concrete building blocks and the like, and the product thereof.

In the manufacture of such blocks, made of a 5 suitable aggregate such as sand and gravel, cinders, etc. mixed with cement and water and subjected to pressing or tamping operations, it is de-, sirable in some cases to secure a smooth or approximately smooth outer surface. In my prior patents No. 1,651,420, 1,682,359, 1,692,355 and 1,987,721 are disclosed means and the method of so treating one side of a block. Such treatment to that extent has proven generally satisfactory except that it provides for a one side operation only,

15 and that horizontally, or in parallelism with the length of the block.

In connection with the manufacture and use of such blocks,

.iect matter of this application. ,0 In connection with the further description reference will be made to the accompanying drawings showing one preferred form of apparatus which may be employed, in which:

Fig. 1 is a plan view of a block forming ma- 5 chine and actuating mechanism for the surfacing means;

Fig. 2 is a longitudinal sectional view on the line II-1I of Fig. 1; i

Fig. 3 is a sectional view like Fig. 2, showing I the feeding hopper in registering depressing position over the vibrating casing;

Fig. 4 is a transverse vertical section on the line IV-IV of Fig. 1;

Fig. 5 is a perspective view of the block forming and smoothing casing, detached;

1936, Serial No. 60,073

Fig. 6 is a similar view of the finished block.

In carrying out the method, I utilize a more or less conventional rectangular housing box 2 consisting of parallel sides and ends, having strengthening flanges and usually bolted together to form 5 ried upon a conventional foundation and rigidly connected with the main frame 2, such parts comprising the main surrounding housing for the '10 inner aggregate receiving cavity.

The inner faces of the sides and ends of the mam housing 2 are planed or otherwise surfaced to provide smooth even sliding faces for the interior block forming casing 4. Such casing is 15 rectangular, its sides and ends being integral or welded or otherwise secured together at the coreasily slidable means.

Resting upon the bottom 3 is the usual pallet 5, fitting freely within ly hold the roller l5 into operative contact with abrasive sand thecam, and to lower the outer end of the lever alternately after being elevated by the high point of the cam. By such means, or any similar corresponding means, it will be observed that a corresponding comparatively rapid up and down movement will be transmitted to casing 4 within its housing by the opposite lever terminals in.

For the purpose of delivering plastic aggregate, a feeding hopper [8 may be provided moving horizontally on a suitable trackway support IS in the plane of the upper edge'20 of the casing when lowered to the plane of the top of housing 2, as in Fig. 3. Hopper 18 with its charge of aggregate is movable over its trackway l9 and the top flanged surface of housing 2 without necessarily stopping motor M, the hopper in such position holding casing 4 downwardly, as in Fig, 3. To facilitate its movement over the upper edges of the casing the lower edge 2| of the front wall of the hopper is rounded as shown, the casing being free to continue functioning when the hopper is retracted for a new charge, as in Fig. 2.

Hopper l8 having been moved over to registering position with the interior of casing 4, its charge of aggregate is deposited in the casing, preferably in a series of properly limited amounts, and subjected to the usual tamping, pressing, vibrating or jolting operations. During such compression, as by tampers b, the casing 4 is continuously reciprocated directly in the line of compression whereby there is imparted to the side and end faces of the block-in-process the desirable trowelling or smoothing treatments.

Such operation continues until the casing is filled with properly tamped aggregate, the tamps being then elevated for clearance of the hopper, and their operation arrested. The hopper is then moved over top edges 20, cleanly shearing off and removing any surplus and leaving the upper surface of the block comparatively flat and smooth.

Casing 4 being still active, the formed unit is then ejected by elevating pallet 5 and the formed unit for removal and drying, leaving the casing temporarily inactive by suitable control of the motor, and ready for the next subsequent operation.

It will be observed that by such treatment the side and end surfaces of the block will be left in a highly condensed smooth surface condition. As stated before, the direction of the trowelling action being at all times vertical, i. e., transverse of the side or end face, and alternating, the surface will be substantially smooth. The surfaces are also characterized by minute direction lines and grooves. due to the inherent character of the aggregate itself, grains of or the like, slight imperfections in the inner surfaces of the casing, or to very minute groove forming ridges in the metal surfaces of the casing.

An additional desirable result is that the vertical movement of the casing also tends to draw the material toward the bottom of the interior cavity, tending to further complete densification and a greater uniformity of the resulting block from top to bottom throughout its several outer surfaces.

Also that the minute lining or grooving resulting from the treatment gives the exposed surfaces of the block, when finished and when laid in a wall, the desirable quality of facilitating the down flow of rain water and avoiding or reducing any tendency to capillary attraction or lodgment thereof.

This quality of the block will be understood by reference to Fig. 6 showing an entire block as made and hardened. It shows the upper one of the opposite load bearing'faces c, an end face (1, and a side'face e. Said side and end faces are substantially smooth, due to the transverse, i. e. vertical, movement thereover of the casing faces, and the minute grooves from one load bearing face across to the other, are suggested or indicated by the lining shown.

A further advantage resulting from the vertical vibration or oscillation of the casing is that it facilitates placement of the pallet 5, avoiding binding and interfering friction in its movement towards the bottom of the casing.

It will be understood also that in making such blocks the corners thereof ordinarily terminate in right angled edges, but that if desired, as for corner blocks, one or more of the corners of the casing may be rounded or filleted for a round cornered block.

The construction of the machine, its method of operation, the method of manufacture, and the features and advantages of the resulting block will be readily understood and appreciated from the foregoing description. The blocks of any rectangular form may vary greatly in size and dimensions, and may be either solid or cored as preferred. the principal effect in view being the outer-surface treatment as described. Such blocks are also easily adapted to any outer supplemental treatment as by painting, white washing, or the like, such being capable of being applied more rapidly and easily and with less material than upon the ordinary rough surface blocks of commerce.

The improvement and advantages over my prior constructions and method disclosed in the patents referred to is in the amplification of treatment and in the generation of the desirable more or less observable vertical pattern of the generally smooth face or faces. The invention is capable of being carried out in the apparatus disclosed or by other suitable means, and is to be understood as not necessarily limited to manufacture in the particular machine of the drawings.

Having described my invention, what I claim 1. The method of making a concrete building block consisting in compressing plastic aggregate in a mold by a tamping action and smoothing a face of the block during the tamping action by a trowelling action in a direction parallel to the direction of tamping.

2. The method of making a concrete building block consisting in compressing plastic aggregate in a mold by a tamping action and smoothing certain faces of the block during the tamping action by a trowelling action in a direction parparallel to the direction of tamping.

3. The method of making a concrete building block consisting in compressing plastic aggregate in a mold and smoothing a face of the block during compressing action by a trowelling action in a direction parallel to the direction of compression. I

FRANCIS J. STRAUB. 

